Once upon a time, there was a guest on David Letterman’s show — don’t remember if it was on NBC or CBS — who was billed as having the perfect foot, the standard by which shoemakers judge their lasts. I remember very little about her except her size, which was either a 6 or a 6½, decidedly smaller than average, and I speak as someone who (for a short time) dated a woman who wore a size 4.

U.S. shoe makers including Stuart Weitzman and Cole Haan report average sizes are creeping up. And retailers are watching the extended-size market carefully. Nordstrom has seen strong sales of larger sizes, says Anne Egan, national merchandise manager for salon shoes. It has held special in-store events for extended-size customers, including women who wear up to a size 14 and men who wear up to a size 20. Long Tall Sally, a U.K.-based apparel and footwear retailer that gets almost half its sales from North America, sells the most shoes in U.S. sizes 12 and 13, says Chief Executive Andrew Shapin. Size 15, added earlier this year, now makes up 10% of its footwear business.

I’m hoping this means that a men’s size 14 will soon be common enough to stock in places that don’t routinely charge me three figures a pair — and then I think of Shaquille O’Neal, always reported as size 22, who now claims to wear a 23. (And truth be told, I might be a candidate for 15s now, or at least an additional E on my 14s.)

As a biologist, I’d argue that reduction in childhood disease and better nutrition are allowing more people to reach their full genetic x environmentally determined height (which would carry with it bigger feet), but that’s not something that can be panicked over.